An Etymological Dictionary of Astronomy and Astrophysics

A → rank 2, → symmetric tensor R_μν that is a contraction of the → Riemann curvature tensor R^λ_μνλ. More specifically, R_μν ≡ Σ (λ) R^λ_μνκ =
R^λ_μνκ. Closely related to the Ricci tensor is the → Einstein tensor, which plays an important role in the theory of → general relativity.

See also: Named after the Italian mathematician Gregorio Ricci-Curbastro (1853-1925); → tensor.